Efficient 2-Nitrophenol determination based on ultra-sonochemically prepared low-dimensional Au-nanoparticles decorated ZnO-chitosan nanocomposites by linear sweep voltammetry

Abstract

In this study, linear sweep voltammetry (LSV) was implemented for the sensitive detection of 2-nitrophenol (2-NP) in phosphate buffer solution (PBS) at pH 7.00 with lab-made nanocomposite materials for environmental remediation. Initially, a flat glassy carbon electrode (GCE) modified using the inorganic-organic binary Au-NPs@ZnO/CTSN(Chitosan) nanocomposites (NCs) was used as a working electrode (WE). The NCs of Au NPs@ZnO/CTSN were basically prepared by an ultra-sonochemical process and fabricated on a GCE using conducting coating binder such as PEDOT:PSS. Before the electrochemical examination, the Au NPs@ZnO/CTSN NC was fully characterized by Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy-dispersive X-ray Spectroscopy (EDS), Brunauer-Emmett-Teller (BET), X-Ray Diffraction analysis (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), and X-Ray Photoelectron Spectroscopy (XPS) to analyze the functional, morphological, structural, elemental, surface area, crystallinity, and binding energy analyses. A linear concentration range (LDR) of 2-NP from 15⁓150 μM was evaluated by LSV in room conditions. From the slope of the calibration curve, the sensor sensitivity was calculated and found to be 20.9905 μAμM⁻¹cm⁻². At signal/noise ratio of 3, the lower limit of detection (LOD) is obtained as 0.45 ± 0.023 μM. Additionally, pH optimization, sensor-probe characterization, stability, and validity are fully analyzed in identical conditions by LSV. Besides this, the assembled 2-NP sensor probe as Au NPs@ZnO/CTSN NCs/PEDOT:PSS/GCE for validity test was performed elaborately and found the reliable and satisfactory results. This is a new approach to the development of electrochemical sensors for environmental chemical analysis using an electrochemical process with gold-nanoparticle decorated ZnO-chitosan for the safety of environmental and healthcare fields on a broad scale.